body {
  overflow: hidden;
}
/* Header */
.large-header {
  position: relative;
  width: 100%;
  background: #333;
  overflow: hidden;
  background-size: cover;
  background-position: center center;
  z-index: 1;
}
.content-item {
  display: flex;
  position: absolute;
  justify-content: space-evenly;
  align-items: center;
  left: 17%;
  top: 20%;
  width: 1000px;
  z-index: 9999;
}
audio {
  position: absolute;
  z-index: 999;
  left: 41.5%;
  bottom: 28%;
  width: 250px;
  height: 30px;
  opacity: 0.5;
}
/* 卡片样式 */
.card {
  width: 270px;
  height: 360px;
  border-radius: 20px;
  background: #14121261;
  position: relative;
  padding: 1.8rem;
  border: 2px solid #d8d9dd63;
  transition: 0.5s ease-out;
  overflow: visible;
  /* 新添加的 */
  transition: all 0.5s;
}
.card-details {
  color: rgb(241, 239, 239);
  height: 100%;
  gap: 0.5em;
  display: grid;
  place-content: center;
}
.card-details a {
  color: #f5f8fb;
}
/* 按钮 */
.card-button {
  transform: translate(-50%, 125%);
  width: 60%;
  border-radius: 0.5rem;
  border: none;
  background: linear-gradient(to bottom, #868f96 0%, #596164 100%);
  /* background-color: #f6d30c; */
  color: #f9f3f3;
  font-size: 1.5rem;
  padding: 0.5rem 1rem;
  position: absolute;
  left: 50%;
  bottom: 0;
  opacity: 0;
  transition: 0.3s ease-out;
}

/* 边框线 */
/*Hover*/
.card:hover {
  border-color: #f5f8fb;
  box-shadow: 0 4px 18px 0 rgba(0, 0, 0, 0.25);
}

.card:hover .card-button {
  transform: translate(-50%, 50%);
  opacity: 1;
}
/* 小熊的样式 */
.bear {
  position: absolute;
  width: 200px;
  height: 100px;
  bottom: 30px;
  background: url(../img/1.png) no-repeat;
  /* 我们元素可以添加多个动画， 用逗号分隔 */
  animation:
    bear 0.4s steps(8) infinite,
    move 10s linear infinite;
  z-index: 999;
  animation-iteration-count: infinite;
}

@keyframes bear {
  0% {
    background-position: 0 0;
  }
  100% {
    background-position: -1600px 0;
  }
}

@keyframes move {
  0% {
    left: 0;
  }
  100% {
    left: 90%;
    transform: translateX(-50%);
  }
}
/* 星星点点样式 */
@keyframes rotate {
  0% {
    transform: perspective(400px) rotateZ(20deg) rotateX(-40deg) rotateY(0);
  }
  100% {
    transform: perspective(400px) rotateZ(20deg) rotateX(-40deg)
      rotateY(-360deg);
  }
}
.stars {
  transform: perspective(500px);
  transform-style: preserve-3d;
  position: absolute;
  bottom: 0;
  perspective-origin: 50% 100%;
  left: 50%;
  animation: rotate 90s infinite linear;
  z-index: 999;
}

.star {
  width: 2px;
  height: 2px;
  background: #d7d7d1;
  position: absolute;
  top: 0;
  left: 0;
  transform-origin: 0 0 -300px;
  transform: translate3d(0, 0, -300px);
  backface-visibility: hidden;
  z-index: 999;
}
/* 原有的 */
.demo-1 .large-header {
  background-image: url('../../gitee背景/img/demo-3-bg.jpg');
}

.main-title {
  position: absolute;
  margin: 0;
  padding: 0;
  color: #f9f1e9;
  text-align: center;
  top: 50%;
  left: 50%;
  -webkit-transform: translate3d(-50%, -50%, 0);
  transform: translate3d(-50%, -50%, 0);
}

.demo-1 .main-title {
  text-transform: uppercase;
  font-size: 4.2em;
  letter-spacing: 0.1em;
}

@media only screen and (max-width: 768px) {
  .demo-1 .main-title,
  .demo-3 .main-title,
  .demo-4 .main-title {
    font-size: 3em;
  }

  .demo-2 .main-title {
    font-size: 4em;
  }
}
